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Distribution of perfluoroalkyl compounds in Osaka Bay and coastal waters of Western Japan
Chemosphere 170 (2017) 260e265
Contents lists available at ScienceDirect
Chemosphere journal homepage: www.elsevier.com/locate/chemosphere
Short Communication
Distribution of perfluoroalkyl compounds in Osaka Bay and coastal waters of Western Japan Vladimir P. Beskoski a, b, *, Katsuya Yamamoto c, Atsushi Yamamoto d, Hideo Okamura e, Mitsuru Hayashi f, Takeshi Nakano g, Chisato Matsumura c, Keiichi Fukushi e, Shinpei Wada f, Hideyuki Inui b, ** a
University of Belgrade, Faculty of Chemistry, P.O. Box 51, Belgrade, Serbia Research Center for Environmental Genomics, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe, Hyogo 657-8501, Japan Hyogo Prefectural Institute of Environmental Sciences, 3-1-18 Yukihira-cho, Suma-ku, Kobe 654-0037, Japan d Osaka City Institute of Public Health and Environmental Sciences, 8-34 Tojocho, Tennoji-ku, Osaka 543-0026, Japan e Graduate School of Maritime Sciences, Kobe University, 5-1-1 Fukaeminami, Higashinada-ku, Kobe, Hyogo 658-0022, Japan f Research Center for Inland Seas, Kobe University, 5-1-1 Fukaeminami, Higashinada-ku, Kobe, Hyogo 658-0022, Japan g Research Center for Environmental Preservation, Osaka University, Yamadaoka 2-4, Suita, Osaka 565-0871, Japan b c
h i g h l i g h t s
g r a p h i c a l a b s t r a c t
PFAAs were analyzed in sediment and seawater samples from coastal waters of Western Japan. The highest concentration of SPFAA was determined in Ajifu Water way in Osaka. The SPFAA in seawater samples ranged between the LOQ and 53.4 ng L1. PFHxA was the most prevalent with the highest concentration of 37 ng L1. PFAAs in surface waters are influenced mainly by sources from the Yodo River basin.
a r t i c l e i n f o
a b s t r a c t
Article history: Received 11 August 2016 Received in revised form 5 December 2016 Accepted 7 December 2016 Available online 10 December 2016
Perfluoroalkyl acids (PFAAs) including perfluoroalkyl sulfonates (PFSAs) and perfluoroalkyl carboxylates (PFCAs) were analyzed in sediment samples taken from Ajifu Waterway in Osaka city, from Osaka Bay, and from Kagoshima Bay, as well as in fifteen seawater samples collected from Osaka Bay and coastal waters of Western Japan. In all sediment samples, only PFCAs were detected, and the highest concentration was determined in Ajifu Waterway, where SPFAA was 58990 ng kg1 dry weight. The total concentrations of PFAAs in sea water samples ranged between the limit of quantification and 53.4 ng L1, and perfluorohexanoic acid was the most prevalent and had the highest concentration of 37 ng L1. The changes in the patterns and concentrations of PFAAs in Osaka Bay and coastal waters of Western Japan indicate that the PFAAs in surface waters are influenced by sources from Keihanshin Metropolitan Area,
Handling Editor: I. Cousins Keywords: Perfluorinated compounds
* Corresponding author. University of Belgrade, Faculty of Chemistry, P.O. Box 51, Belgrade, Serbia. ** Corresponding author. Research Center for Environmental Genomics, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe, Hyogo 657-8501, Japan E-mail addresses: [email protected] (V.P. Beskoski), [email protected] (H. Inui). http://dx.doi.org/10.1016/j.chemosphere.2016.12.028 0045-6535/© 2016 Elsevier Ltd. All rights reserved.
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mainly the Yodo River basin, and the dilution effect which naturally occurs during their transport to the Pacific Ocean. © 2016 Elsevier Ltd. All rights reserved.
1. Introduction The two most studied perfluoroalkyl acids (PFAAs) are perfluorooctanoic acid (PFOA, C7F15COOH) and perfluorooctane sulfonic acid (PFOS, C8F17SO3H) (Domingo, 2012). PFOS, including its form as salts and its precursor, perfluorooctane sulfonyl fluoride, is classified as a persistent organic pollutant (POP, Stockholm Convention, 2012). A number of studies have reported their bioaccumulative and toxic properties, and the ubiquitous distribution of PFAAs in the environment, wildlife and humans because of their physico-chemical properties and their persistence (Haug et al., 2011; Domingo, 2012). After Tokyo, the second largest urban region in Japan with nearly 19 million inhabitants is Keihanshin Metropolitan Area. This area encompasses metropolitan areas of the cities of Osaka in Osaka Prefecture, Kobe in Hyogo Prefecture and Kyoto in Kyoto Prefecture. Keihanshin surrounds Osaka Bay, the semi-enclosed bay located in Western Japan (Fig. 1). The major river in this area is the Yodo River, which receives water from Lake Biwa, the largest lake in Japan, through the Uji River and water from two other upstream rivers, the Katsura River and the Kizu River. The Yodo River has 19 intakes for drinking water for various cities, along with 12 discharge sites from wastewater treatment plants, before finally, flowing into Osaka Bay. As a result of predominantly human activities, much nutrient is loaded out to Osaka Bay,
organic matter is accumulated at the bottom, and nutrients are released from the bottom sediment. Because of the polar nature of PFAAs, the aquatic environment is a primary phase in the environment to harbor these chemicals (Ahrens et al., 2010). Many studies have confirmed that concentrations of PFAAs in the rivers of Keihanshin Metropolitan Area were higher than in other districts of Japan (Saito et al., 2004; Lein et al., 2008; Takagi et al., 2008). Although high PFOA concentrations have been detected in the river, information on levels of PFAAs in Osaka Bay is scarce (Takemine et al., 2014). The objective of our study was to investigate the occurrence, spatial distribution, and pattern of PFAAs in the aquatic environment i.e. in seawater samples (W1-W15) from Osaka Bay, Kii Channel, and coastal waters of Western Japan from Osaka to Kagoshima Bay as well as in sediment samples (S1-S4) from Osaka Bay and Kagoshima Bay. Although there are several recent studies on PFAA pollution in the rivers which discharge their waters to Osaka bay (Takemine et al., 2014; Niisoe et al., 2015), we wanted to confirm our hypothesis that Osaka bay is a source of pollution for the western part of the Pacific Ocean near Japan. Our study will contribute to further understanding of the distribution of PFAAs in these waters in Japan and in the Pacific Ocean, which is important for the protection of environment and human health as well as for future remediation measures for polluted sediment.
Fig. 1. Sampling locations in the Osaka bay, Kagoshima bay, and coastal waters of Western Japan. The arrow represents ocean currents in the Pacific Ocean.
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2. Materials and methods 2.1. Chemicals A standard solution PFAC-MXB of perfluorocarboxylic acids (PFCAs) and perfluoroalkyl sulfonic acids (PFSAs) and a standard solution MPFAC-MXA of mass-labeled PFCAs and PFSAs were purchased from Wellington Laboratories, Inc., Guelph, Canada and had individual chemical purities of >98%. All solvents used were HPLC grade (Wako Pure Chemical Industries, Ltd., Osaka, Japan). 2.2. Sample collection Fifteen seawater samples were collected from Osaka Bay, Kii Channel, the Pacific Ocean, and Kagoshima Bay (W1-W15) as well as sediment samples from the Osaka Bay mouth of the Yodo River (S1), south from Kansai International Airport (S2), from Kagoshima Bay (S3), and from Ajifu Waterway (S4) (Fig. 1). The water samples were collected from a depth of 5 m using a peristaltic pump with a flow rate of about 1 L min1 installed on board a ship. The water samples were collected in new 1L polypropylene containers with narrow mouths and screwtops. The sampling containers were rinsed with methanol, Milli-Q water and water from the individual sampling points prior to use. The use of Teflon bottles and Teflonlined caps was avoided throughout the analysis, to avoid interference. Sediment samples (the top 15 cm) were collected using a standard Ekman sediment sampler from a water depth of 17 m in Osaka Bay and 11 m in Kagoshima Bay. The samples were collected from the ship during a sampling campaign from August 26e28, 2014. 2.3. Sample extraction Extraction of water samples was conducted on board the ship. Water samples were filtered with a glass filter (GC-50, Toyo Roshi Kaisha, Ltd., Tokyo, Japan). One liter of each sample was spiked with 20 mL MPFAC-MXA solution (each 100 pg mL1 in methanol) as mass-labeled surrogates. The sample was then mixed with 60 mL formic acid and extracted with a solid-phase extraction (SPE) cartridge (Presep PFCII; Wako Pure Chemical Industries). SPE was preconditioned with 10 mL of 0.1% ammonium/methanol, then 10 mL of methanol, and finally 15 mL of Milli-Q water. The cartridges were washed with 10 mL Milli-Q water. The eluates were obtained using 5 mL 0.1% ammonium/methanol and concentrated to 1 mL by using a gentle nitrogen stream. Labeled 10 mL of 13 C8PFOA (100 pg mL1 in methanol) was added as a syringe spike. Extraction of sediment samples was conducted in the laboratory as previously described (Beskoski et al., 2013). In brief, 5 g of homogenized sediments, previously dried to 105 C were extracted three times using 10 mL of methanol and ultrasonic extraction. MPFAC-MXA was spiked into each sediment sample before addition of methanol. After reducing the volume to 5 mL, 100 mL of Milli-Q water and 20 mL of formic acid were added, and the sample was extracted with preconditioned SPE. Further, the samples were extracted in the same manner as the water samples. All results of the sediment samples analyses were calculated according to dry matter. The fifteen perfluorinated compounds analyzed including perfluorinated carboxylates (C4-C14) and perfluorinated alkyl sulfonates (C4, C6, C8, and C10) are listed in Table S1. 2.4. PFAA analysis Each final solution was analyzed by LC-MS/MS using a Xevo tandem quadrupole (TQ) MS (Nihon Waters K. K., Tokyo, Japan) coupled with an Acquity UPLC (Nihon Waters K. K.) equipped with a
UPLC BEH C18 column (Nihon Waters K. K.) using negative electrospray ionization with multiple reaction monitoring as previously described by Takemine et al. (2014). Ammonium acetate (2 mM) and acetonitrile were used as a mobile phase under the gradient conditions: 1%e95% of acetonitrile in 8 min, 95% of acetonitrile in 9 min, and 95%e1% of acetonitrile in 9.1 min. The monitored transitions of analytes and surrogates used for quantification and confirmation are given in Table S2. Recovery rates (76e107%) were determined by spiking 200 mL Milli-Q water with 2 ng of all PFAA analytes using PFAC-MXB and conducting sample preparation and analysis in the same manner as for the samples (n ¼ 5). By spiking 200 mL of seawater (n ¼ 1) and 1 g of sediment (n ¼ 5) with 5 ng of all PFAA analytes using PFAC-MXB a matrix spike recovery test was conducted. Recovery rates for seawater and sediment were 87e127% and 52e100%, respectively. PFAAs in the seawater and sediment samples were also analyzed without spiking and the recovery rates for the matrix spike test were calculated by subtracting the amount of PFAAs originally contained in the samples. 2.5. Quality control and quality assurance The instrument limit of detection (LOD) was empirically defined as the injected amount producing a signal-to-noise ratio of 3, and the limit of quantification (LOQ) was defined as the injected amount producing a signal-to-noise ratio of 10. The method detection limit (MDL) and the method quantification limit (MQL) were determined by dividing the LOD and LOQ by the concentration factor. The MDLs for the PFCAs and PFSAs in seawater were 0.1 ng L1 and 0.2 ng L1, respectively. The MQLs of PFCAs and PFSAs in the seawater were 0.3 ng L1 and 0.6 ng L1, respectively. The MDLs for the PFCAs and PFSAs in sediment were 10 ng kg1-dry weight (dw) and 20 ng kg1-dw, respectively. The MQLs of PFCAs in sediment were 30 ng kg1-dw. All PFAA analytes in the laboratory blank (n ¼ 1), confirmed conducting sample preparation and analysis in the same manner as for the water and sediment samples were less than the MDLs. A laboratory blank was included with each sample batch. 2.6. Other measurements Sample pH, temperature, conductivity, salinity, chlorophyll concentrations, and ocean currents were determined during the sampling campaign. 2.7. Statistical analysis The OriginPro 8.0 program was used for determination of Pearson's correlation coefficients. 3. Results and discussion 3.1. PFAA distributions in Osaka Bay and coastal waters of Western Japan Out of fifteen analyzed PFAAs, nine were detected in water samples at concentrations higher than the MDL (PFBA, PFPeA, PFHxA, PFHpA, PFOA, PFNA, PFDA, PFBS, and PFOS). The total concentration of PFAAs (SPFAAs) in seawater samples ranged between the MDL and 53.4 ng L1 (Fig. 2a, Table S5). Relatively higher levels occurred in Osaka Bay (W1-W4) as compared to Kii Channel (W5), the Pacific Ocean south from Shikoku Island (W6-W12), and Kagoshima Bay (W13-W15). The highest concentration of PFAAs was determined in sample W1, located at the mouth of the Yodo River, suggesting that the waters of the Yodo River are contributing to the pollution of Osaka Bay. Previous surveys showed that the
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Fig. 2. Spatial distribution (a) of individual PFAAs in surface water samples obtained from Osaka Bay and coastal waters of Western Japan and relationship between salinity and PFAAs (b), and turbidity and PFAAs (c) Pearson's correlation coefficients were shown in the graphs.
concentrations in surface water of the Yodo River basin varied from 0.4 to 123 ng L1 for PFOS and 4.2e2600 ng L1 for PFOA (Lein et al., 2008). Lein et al. also showed the average concentrations in main stream sites of the Yodo River were 3e4 ng L1 for PFOS and 23e33 ng L1 for PFOA (Lein et al., 2008). Saito et al. found that the concentration of PFOS in the Yodo River ranged from 5.4 to 27.3 ng L1, and that the highest PFOA concentration of 141 ng L1 was in surface water from the Yodo River (Saito et al., 2003, 2004). These studies showed that the main sources of PFOS and PFOA were effluents from three sewage treatment plants at Katsura River (upstream of the Yodo River). The amounts of PFOS and PFOA discharged into Osaka Bay through the Yodo River were estimated to be 64 and 375 g d1, respectively (Lein et al., 2006). In all collected samples in the current study which contained PFAAs, PFHxA was the most prevalent of the PFAAs, with the highest concentration of 37 ng L1. Relative amounts of PFHxA in SPFAAs ranged between 63% (W2) and 82% (W6). The second most abundant was PFOA, and the highest concentration was detected in sample W1 at a concentration of 6.2 ng L1. The other PFCAs, such as PFNA and PFBA, were detected at low concentrations only in W1 and W2, while long-chain PFCAs were not detected. The composition of PFAAs in the environment and their profile can be changed as a result of modifications in production and application patterns. Some companies have switched to shorter chain C6 PFAAs such as PFHxA to replace C8 chemicals such as PFOA (Daikin Industries Ltd., 2007).
Wang et al. reported that shorter chain PFCAs have been emitted historically in large quantities (Wang et al., 2014). Water from Osaka Bay is carried via the Kii Channel to the Pacific Ocean, and it can be concluded that surface and ground waters of the Kansai area contribute to PFAA pollution of the Pacific off Western Japan. This is supported by the predominant PFAA, PFHxA, being detected in a seawater sample taken from W8, located in the open ocean, 50 km away from the nearest shore of Shikoku Island (Fig. 2a and Table S5). Whereas the north coast of Shikoku Island is an industrialized area, the south coast of Shikoku can be regarded as less industrialized. Because of that, the main source of pollution of these open ocean waters seems likely to be Osaka Bay. Concentrations of PFOA and PFOS were strongly positively correlated (R2 ¼ 0.853), and had similar profiles, even though the concentration of PFOA was 10 times higher than PFOS (Fig. S1a). The relationships of PFOA, PFOS, and PFHxA to SPFAAs were also examined (Figs. S1bed). High linearity with determination coefficients of 0.902, 0.907 and 0.997 was observed for these three compounds, respectively. Since the spatial pattern of PFAAs did not vary in the water samples W1-W8, the high linearity suggested that PFAAs arrive from one source into Osaka Bay. If that is the case, the Yodo River basin must be considered the likely source, and PFAAs delivered by this water source could be uniformly spreading toward the Pacific Ocean. However, further research is needed to confirm the incidence and spread of PFAAs from Osaka Bay to the Pacific Ocean and to develop
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a model of contaminant spread. The distribution between sediment and water is a key process which determines the fate of PFAAs, because sediment acts as a sink for PFAAs (Li et al., 2011). Since the layer of sediment in our samples encompassed only the top 15 cm, the PFAA concentrations in these sediments reflect recent contamination. Four sediment samples (S1-S4) were analyzed and the concentrations of PFHxA, PFHpA, and PFOA were the same in S1 and S2 which were located within 20 km of each other in Osaka Bay. However, the dominant PFAAs in S2 were those with longer perfluorinated alkyl chains such as PFNA, PFDA, and PFUnDA. This suggests that PFAAs in S2 had a different pollution source than PFAAs in S1. The highest concentration of PFAAs was determined in the sediment sample taken from Ajifu Waterway (S4) in Osaka (58990 ng kg1 dw).
transport of volatile precursor compounds. Our study supports the first hypothesis, and is in accordance with previous findings, that oceanic currents are the means for the spread of ionic PFAAs (Cai et al., 2012; Armitage et al., 2009; Prevedouros et al., 2006). 4. Conclusions According to our study, the changes in PFAA patterns and concentrations in Osaka Bay and coastal waters of Western Japan indicate that the PFAAs in surface waters are influenced by sources from Keihanshin Metropolitan Area, mainly the Yodo River basin, and the dilution effect which naturally occurs during their transport to the Pacific Ocean. In the future, further study is needed to analyze the possible transfer of PFHxA and other shorter-chain PFAAs to biota in the enclosed aquatic environment of Osaka Bay.
3.2. Basic parameters from sampling points The average flow of the Yodo River is 267 m3 s1, and the population of the Yodo River basin numbers more than ten million people. Inflow from the Yodo River caused low salinity and high chlorophyll concentration and turbidity in W1e3, which were located in Osaka Bay (Fig. 1 and Table S4). Kagoshima Bay is also a semi-enclosed bay, but the influence of river water on the bay water was not as strong as that of the Yoda River on Osaka Bay (Table S4). This was likely because the human population living on the river watershed which flows into Kagoshima Bay is approximately one-tenth of that of the Yodo River. The reduced pH in W15 was attributed to activity of the active volcano, Mt. Sakurajima (Table S4). Determination of basic parameters has confirmed that fresh water carried by rivers has a strong influence on the chemistry of enclosed marine areas into which the watercourses drain. Furthermore, it would be expected that the distribution of several waterborne contaminants in Osaka Bay would be similar to each other and that correlation of PFAAs with salinity and turbidity may exist. Linearity with high determination coefficients between salinity and PFAAs (R2 > 0.9) (Fig. 2b), and between turbidity and PFAAs (R2 > 0.8) (Fig. 2c) confirmed that the distribution of PFAAs in Osaka Bay depends on fresh water distribution, ocean currents, and mixing. 3.3. Comparison of PFAA concentrations with those determined in previously published studies The number of studies published on PFAAs has increased considerably during recent years. However, in most cases, only concentrations of PFOS and PFOA were reported. In Table S6, concentrations of PFAAs in sea and ocean water reported in the literature are given. The highest concentration was determined in the coastal sea area of Hyogo prefecture, Japan, suggesting significant contamination with PFHxA (Takemine et al., 2014). The PFHxA concentration we detected was 10 times lower than the concentration determined in the study by Takemine et al. (2014). However, seawater sampled at W1 had a PFHxA concentration three times higher than the German Bight maximum value (Ahrens et al., 2009). The concentration of PFOA in Osaka Bay determined in our study was two times lower than the concentration in the coastal sea area of Hyogo prefecture. The observed PFOA and PFOS concentrations in seawater of Osaka Bay were in the same range as the level of these pollutants in the coastal North Sea (Theobald et al., 2011). Interestingly, PFOA in the Pacific Ocean of Western Japan was in the same range as that determined in the open North Sea (Yamashita et al., 2005; Theobald et al., 2011). There are two main hypotheses for the global transport of PFAAs: direct transport of ionic PFAAs via sea and oceanic currents or long-range atmospheric
Acknowledgements The authors would like to express their gratitude to Captain Dr. Yoshiji YANO, First officer Dr. Nobukazu Wakabayashi, and to the whole crew of the Fukae-maru, Training Ship of Kobe University, Graduate School of Maritime Sciences. For valuable discussion during preparation of the sampling campaign and for useful advice, we are grateful to Dr. Shusuke Takemine from the Center for Environmental Science in Saitama, Japan. This research was supported by the Japan Society for the Promotion of Science, (JSPS) Invitation Fellowship Program for Research in Japan (Long-term) ID No. L-14552. Appendix A. Supplementary data Supplementary data related to this article can be found at http:// dx.doi.org/10.1016/j.chemosphere.2016.12.028. References Ahrens, L., Felizeter, S., Ebinghaus, R., 2009. Spatial distribution of polyfluoroalkyl compounds in seawater of the German Bight. Chemosphere 76, 179e184. Ahrens, L., Taniyasu, S., Yeung, L.W.Y., Yamashita, N., Lam, P.K.S., Ebinghaus, R., 2010. Distribution of polyfluoroalkyl compounds in water, suspended particulate matter and sediment from Tokyo Bay, Japan. Chemosphere 76, 266e272. Armitage, J.M., Macleod, M., Cousins, I.T., 2009. Comparative assessment of the global fate and transport pathways of long-chain perfluorocarboxy acids (PFCAs) and perfluorocarboxylates (PFCs) emitted from direct sources. Environ. Sci. Technol. 43, 5830e5836. Beskoski, V.P., Takemine, S., Nakano, T., Slavkovi c Beskoski, L., Gojgi c-Cvijovi c, G., Ili c, M., Mileti c, S., Vrvi c, M.M., 2013. Perfluorinated compounds in sediment samples from the wastewatercanal of Pan cevo (Serbia) industrial area. Chemosphere 91, 1408e1415. Cai, M., Zhao, Z., Yin, Z., Ahrens, L., Huang, P., Cai, M., Yang, H., He, J., Sturm, R., Ebinghaus, R., Xie, Z., 2012. Occurrence of perfluoroalkyl compounds in surface waters from the north pacific to the arctic ocean. Environ. Sci. Technol. 46, 661e668. Daikin Industries, Ltd., 2007. Elimination of PFOA in Fluorochemical Products. http://www.daikin.com/press/2007/071221/ (Accessed 10 August 2016). Domingo, J.L., 2012. Health risks of dietary exposure to perfluorinated compounds. Environ. Int. 40, 187e195. Haug, L.S., Huber, S., Becher, G., Thomsen, C., 2011. Characterisation of human exposure pathways to perfluorinated compoundseComparing exposure estimates with biomarkers of exposure. Environ. Int. 37, 687e693. Lein, N.P.H., Fujii, S., Takana, S., Nozoe, M., Wirojanagud, W., Anton, A., Lindstrom, G., 2006. Perfluorinated substances in tap water of Japan and several countries and their relationship to surface water contamination. Environ. Eng. Res. Jpn. J. 43, 611e618. Lein, N.P.H., Fujii, S., Tanaka, S., Nozoe, M., Tanaka, H., 2008. Contamination of perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) in surface water of the Yodo River basin (Japan). Desalination 226, 338e347. Li, F., Sun, H., Hao, Z., He, N., Zhao, L., Zhang, T., Sun, T., 2011. Perfluorinated compounds in haihe River and dagu drainage canal in tianjin, China. Chemosphere 84, 265e271. Niisoe, T., Senevirathna, S.T.M.L.D., Harada, K.H., Fujii, Y., Hitomi, T., Kobayashi, H., Yan, J., Zhao, C., Oshima, M., Koizumi, A., 2015. Perfluorinated carboxylic acids discharged from the Yodo River basin, Japan. Chemosphere 138, 81e88. Prevedouros, K., Cousins, I.T., Buck, R.C., Korzeniowski, S.H., 2006. Sources, fate and
V.P. Beskoski et al. / Chemosphere 170 (2017) 260e265 transport of perfluorocarboxylates. Environ. Sci. Technol. 40, 32e44. Saito, N., Harada, K., Inoue, K., Sasaki, K., Yoshinaga, T., Koizumi, A., 2004. Perfluorooctanoate and perfluorooctane sulfonate concentrations in surface water in Japan. J. Occup. Health 46, 49e59. Saito, N., Sasaki, K., Nakatome, K., Harada, K., Yoshinaga, T., Koizumi, A., 2003. Perfluorooctane sulfonate concentrations in surface water in Japan. Arch. Environ. Contam. Toxicol 45, 149e158. Stockholm Convention, 2012. Guidelines on Best Available Techniques and Best Environmental Practices for the Production and Use of Perfluorooctane Sulfonic Acid (PFOS) and Related Chemicals Listed under the Stockholm Convention on POPs (Draft). http://chm.pops.int/ (Accessed 10 August 2016). Takagi, S., Adachi, F., Miyano, K., Koizumi, Y., Tanaka, H., Mimura, M., Watanabe, I., Tanabe, S., Kannan, K., 2008. Perfluorooctane sulfonate and perfluorooctanoate in raw and treated tap water from Osaka, Japan. Chemosphere 72, 1409e1412.
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Chemosphere journal homepage: www.elsevier.com/locate/chemosphere
Short Communication
Distribution of perfluoroalkyl compounds in Osaka Bay and coastal waters of Western Japan Vladimir P. Beskoski a, b, *, Katsuya Yamamoto c, Atsushi Yamamoto d, Hideo Okamura e, Mitsuru Hayashi f, Takeshi Nakano g, Chisato Matsumura c, Keiichi Fukushi e, Shinpei Wada f, Hideyuki Inui b, ** a
University of Belgrade, Faculty of Chemistry, P.O. Box 51, Belgrade, Serbia Research Center for Environmental Genomics, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe, Hyogo 657-8501, Japan Hyogo Prefectural Institute of Environmental Sciences, 3-1-18 Yukihira-cho, Suma-ku, Kobe 654-0037, Japan d Osaka City Institute of Public Health and Environmental Sciences, 8-34 Tojocho, Tennoji-ku, Osaka 543-0026, Japan e Graduate School of Maritime Sciences, Kobe University, 5-1-1 Fukaeminami, Higashinada-ku, Kobe, Hyogo 658-0022, Japan f Research Center for Inland Seas, Kobe University, 5-1-1 Fukaeminami, Higashinada-ku, Kobe, Hyogo 658-0022, Japan g Research Center for Environmental Preservation, Osaka University, Yamadaoka 2-4, Suita, Osaka 565-0871, Japan b c
h i g h l i g h t s
g r a p h i c a l a b s t r a c t
PFAAs were analyzed in sediment and seawater samples from coastal waters of Western Japan. The highest concentration of SPFAA was determined in Ajifu Water way in Osaka. The SPFAA in seawater samples ranged between the LOQ and 53.4 ng L1. PFHxA was the most prevalent with the highest concentration of 37 ng L1. PFAAs in surface waters are influenced mainly by sources from the Yodo River basin.
a r t i c l e i n f o
a b s t r a c t
Article history: Received 11 August 2016 Received in revised form 5 December 2016 Accepted 7 December 2016 Available online 10 December 2016
Perfluoroalkyl acids (PFAAs) including perfluoroalkyl sulfonates (PFSAs) and perfluoroalkyl carboxylates (PFCAs) were analyzed in sediment samples taken from Ajifu Waterway in Osaka city, from Osaka Bay, and from Kagoshima Bay, as well as in fifteen seawater samples collected from Osaka Bay and coastal waters of Western Japan. In all sediment samples, only PFCAs were detected, and the highest concentration was determined in Ajifu Waterway, where SPFAA was 58990 ng kg1 dry weight. The total concentrations of PFAAs in sea water samples ranged between the limit of quantification and 53.4 ng L1, and perfluorohexanoic acid was the most prevalent and had the highest concentration of 37 ng L1. The changes in the patterns and concentrations of PFAAs in Osaka Bay and coastal waters of Western Japan indicate that the PFAAs in surface waters are influenced by sources from Keihanshin Metropolitan Area,
Handling Editor: I. Cousins Keywords: Perfluorinated compounds
* Corresponding author. University of Belgrade, Faculty of Chemistry, P.O. Box 51, Belgrade, Serbia. ** Corresponding author. Research Center for Environmental Genomics, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe, Hyogo 657-8501, Japan E-mail addresses: [email protected] (V.P. Beskoski), [email protected] (H. Inui). http://dx.doi.org/10.1016/j.chemosphere.2016.12.028 0045-6535/© 2016 Elsevier Ltd. All rights reserved.
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mainly the Yodo River basin, and the dilution effect which naturally occurs during their transport to the Pacific Ocean. © 2016 Elsevier Ltd. All rights reserved.
1. Introduction The two most studied perfluoroalkyl acids (PFAAs) are perfluorooctanoic acid (PFOA, C7F15COOH) and perfluorooctane sulfonic acid (PFOS, C8F17SO3H) (Domingo, 2012). PFOS, including its form as salts and its precursor, perfluorooctane sulfonyl fluoride, is classified as a persistent organic pollutant (POP, Stockholm Convention, 2012). A number of studies have reported their bioaccumulative and toxic properties, and the ubiquitous distribution of PFAAs in the environment, wildlife and humans because of their physico-chemical properties and their persistence (Haug et al., 2011; Domingo, 2012). After Tokyo, the second largest urban region in Japan with nearly 19 million inhabitants is Keihanshin Metropolitan Area. This area encompasses metropolitan areas of the cities of Osaka in Osaka Prefecture, Kobe in Hyogo Prefecture and Kyoto in Kyoto Prefecture. Keihanshin surrounds Osaka Bay, the semi-enclosed bay located in Western Japan (Fig. 1). The major river in this area is the Yodo River, which receives water from Lake Biwa, the largest lake in Japan, through the Uji River and water from two other upstream rivers, the Katsura River and the Kizu River. The Yodo River has 19 intakes for drinking water for various cities, along with 12 discharge sites from wastewater treatment plants, before finally, flowing into Osaka Bay. As a result of predominantly human activities, much nutrient is loaded out to Osaka Bay,
organic matter is accumulated at the bottom, and nutrients are released from the bottom sediment. Because of the polar nature of PFAAs, the aquatic environment is a primary phase in the environment to harbor these chemicals (Ahrens et al., 2010). Many studies have confirmed that concentrations of PFAAs in the rivers of Keihanshin Metropolitan Area were higher than in other districts of Japan (Saito et al., 2004; Lein et al., 2008; Takagi et al., 2008). Although high PFOA concentrations have been detected in the river, information on levels of PFAAs in Osaka Bay is scarce (Takemine et al., 2014). The objective of our study was to investigate the occurrence, spatial distribution, and pattern of PFAAs in the aquatic environment i.e. in seawater samples (W1-W15) from Osaka Bay, Kii Channel, and coastal waters of Western Japan from Osaka to Kagoshima Bay as well as in sediment samples (S1-S4) from Osaka Bay and Kagoshima Bay. Although there are several recent studies on PFAA pollution in the rivers which discharge their waters to Osaka bay (Takemine et al., 2014; Niisoe et al., 2015), we wanted to confirm our hypothesis that Osaka bay is a source of pollution for the western part of the Pacific Ocean near Japan. Our study will contribute to further understanding of the distribution of PFAAs in these waters in Japan and in the Pacific Ocean, which is important for the protection of environment and human health as well as for future remediation measures for polluted sediment.
Fig. 1. Sampling locations in the Osaka bay, Kagoshima bay, and coastal waters of Western Japan. The arrow represents ocean currents in the Pacific Ocean.
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2. Materials and methods 2.1. Chemicals A standard solution PFAC-MXB of perfluorocarboxylic acids (PFCAs) and perfluoroalkyl sulfonic acids (PFSAs) and a standard solution MPFAC-MXA of mass-labeled PFCAs and PFSAs were purchased from Wellington Laboratories, Inc., Guelph, Canada and had individual chemical purities of >98%. All solvents used were HPLC grade (Wako Pure Chemical Industries, Ltd., Osaka, Japan). 2.2. Sample collection Fifteen seawater samples were collected from Osaka Bay, Kii Channel, the Pacific Ocean, and Kagoshima Bay (W1-W15) as well as sediment samples from the Osaka Bay mouth of the Yodo River (S1), south from Kansai International Airport (S2), from Kagoshima Bay (S3), and from Ajifu Waterway (S4) (Fig. 1). The water samples were collected from a depth of 5 m using a peristaltic pump with a flow rate of about 1 L min1 installed on board a ship. The water samples were collected in new 1L polypropylene containers with narrow mouths and screwtops. The sampling containers were rinsed with methanol, Milli-Q water and water from the individual sampling points prior to use. The use of Teflon bottles and Teflonlined caps was avoided throughout the analysis, to avoid interference. Sediment samples (the top 15 cm) were collected using a standard Ekman sediment sampler from a water depth of 17 m in Osaka Bay and 11 m in Kagoshima Bay. The samples were collected from the ship during a sampling campaign from August 26e28, 2014. 2.3. Sample extraction Extraction of water samples was conducted on board the ship. Water samples were filtered with a glass filter (GC-50, Toyo Roshi Kaisha, Ltd., Tokyo, Japan). One liter of each sample was spiked with 20 mL MPFAC-MXA solution (each 100 pg mL1 in methanol) as mass-labeled surrogates. The sample was then mixed with 60 mL formic acid and extracted with a solid-phase extraction (SPE) cartridge (Presep PFCII; Wako Pure Chemical Industries). SPE was preconditioned with 10 mL of 0.1% ammonium/methanol, then 10 mL of methanol, and finally 15 mL of Milli-Q water. The cartridges were washed with 10 mL Milli-Q water. The eluates were obtained using 5 mL 0.1% ammonium/methanol and concentrated to 1 mL by using a gentle nitrogen stream. Labeled 10 mL of 13 C8PFOA (100 pg mL1 in methanol) was added as a syringe spike. Extraction of sediment samples was conducted in the laboratory as previously described (Beskoski et al., 2013). In brief, 5 g of homogenized sediments, previously dried to 105 C were extracted three times using 10 mL of methanol and ultrasonic extraction. MPFAC-MXA was spiked into each sediment sample before addition of methanol. After reducing the volume to 5 mL, 100 mL of Milli-Q water and 20 mL of formic acid were added, and the sample was extracted with preconditioned SPE. Further, the samples were extracted in the same manner as the water samples. All results of the sediment samples analyses were calculated according to dry matter. The fifteen perfluorinated compounds analyzed including perfluorinated carboxylates (C4-C14) and perfluorinated alkyl sulfonates (C4, C6, C8, and C10) are listed in Table S1. 2.4. PFAA analysis Each final solution was analyzed by LC-MS/MS using a Xevo tandem quadrupole (TQ) MS (Nihon Waters K. K., Tokyo, Japan) coupled with an Acquity UPLC (Nihon Waters K. K.) equipped with a
UPLC BEH C18 column (Nihon Waters K. K.) using negative electrospray ionization with multiple reaction monitoring as previously described by Takemine et al. (2014). Ammonium acetate (2 mM) and acetonitrile were used as a mobile phase under the gradient conditions: 1%e95% of acetonitrile in 8 min, 95% of acetonitrile in 9 min, and 95%e1% of acetonitrile in 9.1 min. The monitored transitions of analytes and surrogates used for quantification and confirmation are given in Table S2. Recovery rates (76e107%) were determined by spiking 200 mL Milli-Q water with 2 ng of all PFAA analytes using PFAC-MXB and conducting sample preparation and analysis in the same manner as for the samples (n ¼ 5). By spiking 200 mL of seawater (n ¼ 1) and 1 g of sediment (n ¼ 5) with 5 ng of all PFAA analytes using PFAC-MXB a matrix spike recovery test was conducted. Recovery rates for seawater and sediment were 87e127% and 52e100%, respectively. PFAAs in the seawater and sediment samples were also analyzed without spiking and the recovery rates for the matrix spike test were calculated by subtracting the amount of PFAAs originally contained in the samples. 2.5. Quality control and quality assurance The instrument limit of detection (LOD) was empirically defined as the injected amount producing a signal-to-noise ratio of 3, and the limit of quantification (LOQ) was defined as the injected amount producing a signal-to-noise ratio of 10. The method detection limit (MDL) and the method quantification limit (MQL) were determined by dividing the LOD and LOQ by the concentration factor. The MDLs for the PFCAs and PFSAs in seawater were 0.1 ng L1 and 0.2 ng L1, respectively. The MQLs of PFCAs and PFSAs in the seawater were 0.3 ng L1 and 0.6 ng L1, respectively. The MDLs for the PFCAs and PFSAs in sediment were 10 ng kg1-dry weight (dw) and 20 ng kg1-dw, respectively. The MQLs of PFCAs in sediment were 30 ng kg1-dw. All PFAA analytes in the laboratory blank (n ¼ 1), confirmed conducting sample preparation and analysis in the same manner as for the water and sediment samples were less than the MDLs. A laboratory blank was included with each sample batch. 2.6. Other measurements Sample pH, temperature, conductivity, salinity, chlorophyll concentrations, and ocean currents were determined during the sampling campaign. 2.7. Statistical analysis The OriginPro 8.0 program was used for determination of Pearson's correlation coefficients. 3. Results and discussion 3.1. PFAA distributions in Osaka Bay and coastal waters of Western Japan Out of fifteen analyzed PFAAs, nine were detected in water samples at concentrations higher than the MDL (PFBA, PFPeA, PFHxA, PFHpA, PFOA, PFNA, PFDA, PFBS, and PFOS). The total concentration of PFAAs (SPFAAs) in seawater samples ranged between the MDL and 53.4 ng L1 (Fig. 2a, Table S5). Relatively higher levels occurred in Osaka Bay (W1-W4) as compared to Kii Channel (W5), the Pacific Ocean south from Shikoku Island (W6-W12), and Kagoshima Bay (W13-W15). The highest concentration of PFAAs was determined in sample W1, located at the mouth of the Yodo River, suggesting that the waters of the Yodo River are contributing to the pollution of Osaka Bay. Previous surveys showed that the
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Fig. 2. Spatial distribution (a) of individual PFAAs in surface water samples obtained from Osaka Bay and coastal waters of Western Japan and relationship between salinity and PFAAs (b), and turbidity and PFAAs (c) Pearson's correlation coefficients were shown in the graphs.
concentrations in surface water of the Yodo River basin varied from 0.4 to 123 ng L1 for PFOS and 4.2e2600 ng L1 for PFOA (Lein et al., 2008). Lein et al. also showed the average concentrations in main stream sites of the Yodo River were 3e4 ng L1 for PFOS and 23e33 ng L1 for PFOA (Lein et al., 2008). Saito et al. found that the concentration of PFOS in the Yodo River ranged from 5.4 to 27.3 ng L1, and that the highest PFOA concentration of 141 ng L1 was in surface water from the Yodo River (Saito et al., 2003, 2004). These studies showed that the main sources of PFOS and PFOA were effluents from three sewage treatment plants at Katsura River (upstream of the Yodo River). The amounts of PFOS and PFOA discharged into Osaka Bay through the Yodo River were estimated to be 64 and 375 g d1, respectively (Lein et al., 2006). In all collected samples in the current study which contained PFAAs, PFHxA was the most prevalent of the PFAAs, with the highest concentration of 37 ng L1. Relative amounts of PFHxA in SPFAAs ranged between 63% (W2) and 82% (W6). The second most abundant was PFOA, and the highest concentration was detected in sample W1 at a concentration of 6.2 ng L1. The other PFCAs, such as PFNA and PFBA, were detected at low concentrations only in W1 and W2, while long-chain PFCAs were not detected. The composition of PFAAs in the environment and their profile can be changed as a result of modifications in production and application patterns. Some companies have switched to shorter chain C6 PFAAs such as PFHxA to replace C8 chemicals such as PFOA (Daikin Industries Ltd., 2007).
Wang et al. reported that shorter chain PFCAs have been emitted historically in large quantities (Wang et al., 2014). Water from Osaka Bay is carried via the Kii Channel to the Pacific Ocean, and it can be concluded that surface and ground waters of the Kansai area contribute to PFAA pollution of the Pacific off Western Japan. This is supported by the predominant PFAA, PFHxA, being detected in a seawater sample taken from W8, located in the open ocean, 50 km away from the nearest shore of Shikoku Island (Fig. 2a and Table S5). Whereas the north coast of Shikoku Island is an industrialized area, the south coast of Shikoku can be regarded as less industrialized. Because of that, the main source of pollution of these open ocean waters seems likely to be Osaka Bay. Concentrations of PFOA and PFOS were strongly positively correlated (R2 ¼ 0.853), and had similar profiles, even though the concentration of PFOA was 10 times higher than PFOS (Fig. S1a). The relationships of PFOA, PFOS, and PFHxA to SPFAAs were also examined (Figs. S1bed). High linearity with determination coefficients of 0.902, 0.907 and 0.997 was observed for these three compounds, respectively. Since the spatial pattern of PFAAs did not vary in the water samples W1-W8, the high linearity suggested that PFAAs arrive from one source into Osaka Bay. If that is the case, the Yodo River basin must be considered the likely source, and PFAAs delivered by this water source could be uniformly spreading toward the Pacific Ocean. However, further research is needed to confirm the incidence and spread of PFAAs from Osaka Bay to the Pacific Ocean and to develop
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a model of contaminant spread. The distribution between sediment and water is a key process which determines the fate of PFAAs, because sediment acts as a sink for PFAAs (Li et al., 2011). Since the layer of sediment in our samples encompassed only the top 15 cm, the PFAA concentrations in these sediments reflect recent contamination. Four sediment samples (S1-S4) were analyzed and the concentrations of PFHxA, PFHpA, and PFOA were the same in S1 and S2 which were located within 20 km of each other in Osaka Bay. However, the dominant PFAAs in S2 were those with longer perfluorinated alkyl chains such as PFNA, PFDA, and PFUnDA. This suggests that PFAAs in S2 had a different pollution source than PFAAs in S1. The highest concentration of PFAAs was determined in the sediment sample taken from Ajifu Waterway (S4) in Osaka (58990 ng kg1 dw).
transport of volatile precursor compounds. Our study supports the first hypothesis, and is in accordance with previous findings, that oceanic currents are the means for the spread of ionic PFAAs (Cai et al., 2012; Armitage et al., 2009; Prevedouros et al., 2006). 4. Conclusions According to our study, the changes in PFAA patterns and concentrations in Osaka Bay and coastal waters of Western Japan indicate that the PFAAs in surface waters are influenced by sources from Keihanshin Metropolitan Area, mainly the Yodo River basin, and the dilution effect which naturally occurs during their transport to the Pacific Ocean. In the future, further study is needed to analyze the possible transfer of PFHxA and other shorter-chain PFAAs to biota in the enclosed aquatic environment of Osaka Bay.
3.2. Basic parameters from sampling points The average flow of the Yodo River is 267 m3 s1, and the population of the Yodo River basin numbers more than ten million people. Inflow from the Yodo River caused low salinity and high chlorophyll concentration and turbidity in W1e3, which were located in Osaka Bay (Fig. 1 and Table S4). Kagoshima Bay is also a semi-enclosed bay, but the influence of river water on the bay water was not as strong as that of the Yoda River on Osaka Bay (Table S4). This was likely because the human population living on the river watershed which flows into Kagoshima Bay is approximately one-tenth of that of the Yodo River. The reduced pH in W15 was attributed to activity of the active volcano, Mt. Sakurajima (Table S4). Determination of basic parameters has confirmed that fresh water carried by rivers has a strong influence on the chemistry of enclosed marine areas into which the watercourses drain. Furthermore, it would be expected that the distribution of several waterborne contaminants in Osaka Bay would be similar to each other and that correlation of PFAAs with salinity and turbidity may exist. Linearity with high determination coefficients between salinity and PFAAs (R2 > 0.9) (Fig. 2b), and between turbidity and PFAAs (R2 > 0.8) (Fig. 2c) confirmed that the distribution of PFAAs in Osaka Bay depends on fresh water distribution, ocean currents, and mixing. 3.3. Comparison of PFAA concentrations with those determined in previously published studies The number of studies published on PFAAs has increased considerably during recent years. However, in most cases, only concentrations of PFOS and PFOA were reported. In Table S6, concentrations of PFAAs in sea and ocean water reported in the literature are given. The highest concentration was determined in the coastal sea area of Hyogo prefecture, Japan, suggesting significant contamination with PFHxA (Takemine et al., 2014). The PFHxA concentration we detected was 10 times lower than the concentration determined in the study by Takemine et al. (2014). However, seawater sampled at W1 had a PFHxA concentration three times higher than the German Bight maximum value (Ahrens et al., 2009). The concentration of PFOA in Osaka Bay determined in our study was two times lower than the concentration in the coastal sea area of Hyogo prefecture. The observed PFOA and PFOS concentrations in seawater of Osaka Bay were in the same range as the level of these pollutants in the coastal North Sea (Theobald et al., 2011). Interestingly, PFOA in the Pacific Ocean of Western Japan was in the same range as that determined in the open North Sea (Yamashita et al., 2005; Theobald et al., 2011). There are two main hypotheses for the global transport of PFAAs: direct transport of ionic PFAAs via sea and oceanic currents or long-range atmospheric
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